Rollback protection in Damysus

Abstract

Streamlined Byzantine Fault Tolerance (BFT) protocols have been developed to create efficient view-changes. To improve upon their performance, trusted components have been introduced to prevent equivocation within a protocol. However, these trusted components suffer from rollback attacks. We identify clear examples of rollback attacks on Damysus, and design a novel method to mitigate the attack vector. This is done via a pacemaker protocol called Artemis, which allocates trusted components to epochs. Integrating Artemis with Damysus creates Apollo, a streamlined BFT protocol. Apollo is demonstrates to outperform existing streamlined BFT protocols such as Hotstuff, while preventing equivocation due to rollback attacks. This is all done while maintaining the reduced number of communication phases and tolerating a minority of faulty nodes.